The present invention relates to a process for preparing .beta.-lactams (2-azetidinones), and more in particular to a process for preparing N-halo .alpha.,.alpha.-disubstituted .beta.-lactams.
.beta.-Lactams, which are the inner cyclic amides of .beta.-amino acids, are generally made by the action of a Grignard reagent upon .beta.-aminopropionic esters, or by the action of a base upon .beta.-aminopropionic acid chlorides. .beta.-Lactams bearing chloromethyl substituents on the .alpha.-carbon atom and hydrogen on the amido nitrogen atom are prepared by treating an .alpha.,.alpha.-disubstituted .beta.-halopropionic acid amide with selected alkali or alkaline earth metal salts of weakly acidic compounds. This method is described in U.S. Pat. No. 3,297,754.
Amides are known to react with aqueous hypohalite solution to form the corresponding amine by the Hoffman reaction. This reaction is described in more detail by E. S. Wallis in "Organic Reactions", Vol. III, Chap. 7, pp. 267-286.